Earthworm_Reproductive_System and its part.pptx

Earthworms have long cylindrical body.
- The body is divided into more than hundred short segments
which are similar (metameres about 100-120 in number).
- The dorsal surface of the body is marked by a dark median mid
dorsal line (dorsal blood vessel) along the longitudinal axis of
the body.
- The ventral surface is distinguished by the presence of genital
openings (pores).
- Anterior end consists of the mouth and the prostomium, a lobe
which serves as a covering for the mouth and as a wedge to
force open cracks in the soil into which the earthworm may
crawl.
- The prostomium is sensory in function

1. Reproductive System of Earthworm Detailed Presentation by Debasish Doley

2. Introduction Earthworms are hermaphrodites, meaning each individual possesses both male and female reproductive organs. Despite this, cross-fertilization usually occurs between two worms. The reproductive system is highly specialized and includes testes, ovaries, sperm receptacles, and the clitellum.

3. Male Reproductive Organs • Testes are present in the 10th and 11th segments. • Seminal vesicles store and nourish sperm. • Vas deferens transport sperm to male genital pores. • Male genital pores are located in the 18th segment.

4. Female Reproductive Organs • Ovaries are present in the 13th segment. • Oviducts open into female genital pores located in the 14th segment. • Spermathecae are present in segments 6 to 9, used to store sperm from another worm during copulation.

5. Copulation • Two earthworms align ventrally in opposite directions. • Sperm is exchanged and stored in spermathecae. • Cross-fertilization ensures genetic variation.

6. Cocoon Formation • The clitellum secretes a mucous ring that slides forward. • Eggs from the female genital pores and sperm from spermathecae are deposited into this mucous ring. • The ring slips off the body and closes, forming a cocoon.

7. Fertilization & Development • Fertilization occurs within the cocoon. • Zygotes develop directly into juvenile worms. • No larval stage is present (direct development).

8. Significance of Reproduction • Cross-fertilization ensures variation and adaptability. • Efficient reproductive strategy enhances survival. • Earthworm populations contribute to ecological balance and soil fertility.

9. Conclusion The reproductive system of earthworms is complex and well-adapted for survival. Cross-fertilization, cocoon formation, and direct development make them efficient reproducers. Their reproduction plays a key role in maintaining healthy ecosystems.